Why does rebar corrode?

Premature deterioration of reinforced concrete structures has become a serious problem worldwide due to corrosion of the embedded steel. The estimated annual cost of corrosion in the USA for bridges alone exceeds US$8 billion [1] [2]. The structures chiefly affected are those situated in an aggressive environments such as marine and road bridges to which de-icing salts are applied during winter periods. 

Stages of visible deterioration

Main Mechanisms of deterioration - click here

Interaction between Carbonation and Chlorides - click here

Galvanic coupling in concrete - click here

Cracks in concrete facilitate corrosion - click here

Predictive models - click here